Numerical Study on Methane Hydrate Dissociation in Lab-Scale Sandstone Core

Abstract

In current work, a 2D axisymmetric simulation of the gas production from hydrates in a porous sandstone core was conducted to study the behavior of gas production using depressurization method. The core model included three phases: hydrate, methane, and water. The decomposition reaction process, mass transfer, two-phase flow and heat transfer effects were included the model. The Darcy’s law was applied for the two-phase flow of water and gas in porous media and the hydrate was assumed to be stagnant. The Kim et al. (1987) kinetic model was used to determine hydrate dissociation rate and Reported values of the intrinsic rate constant and activation energy by Kim et al. (1987) and Clarke and Bishnoi (2001) were used in kinetic reaction equation in two various cases. In the energy balance equation the heat convection, conduction, consumption associated with hydrate decomposition and transfer from the surroundings were considered as well and the governing equations were solved using Finite Volume method. At last, by comparing the simulation results with experimental data, it is seen that the values of constant parameters of the intrinsic rate constant and activation energy suggested by Clarke and Bishnoi (2001) are more accurate to model hydrate kinetic reaction.